Add timeout to broker test

Cargo.lock

@@ -481,6 +481,12 @@ version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "57c66a976bf5909d801bbef33416c41372779507e7a6b3a5e25e4749c58f776a"
 
+[[package]]
+name = "futures-timer"
+version = "3.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e64b03909df88034c26dc1547e8970b91f98bdb65165d6a4e9110d94263dbb2c"
+
 [[package]]
 name = "futures-util"
 version = "0.3.21"
@@ -1524,6 +1530,7 @@ dependencies = [
  "async-trait",
  "derive-getters",
  "futures",
+ "futures-timer",
  "log",
  "mailparse",
  "serde",

Cargo.toml

@@ -27,3 +27,4 @@ stop-token = "0.7"
 
 [dev-dependencies]
 textwrap = "0.15.0"
+futures-timer = "3.0"

src/email.rs

@@ -159,6 +159,7 @@ mod tests {
         collections::HashMap,
         fmt::{Display, Formatter},
         sync::Arc,
+        time::Duration,
     };
 
     use crate::task::{Cancel, SpawnError};
@@ -170,6 +171,7 @@ mod tests {
         Future, FutureExt, SinkExt,
     };
     use futures::{select, StreamExt};
+    use futures_timer::Delay;
     use thiserror::Error;
 
     #[derive(Error, Debug)]
@@ -306,6 +308,7 @@ mod tests {
         select! {
             msg = message_rx.next() => assert_eq!("hello, world!", msg.expect("empty channel")),
             _ = join_handle.fuse() => panic!("broker returned, but did not receive message"),
+            _ = Delay::new(Duration::from_secs(5)).fuse() => panic!("test timed out"),
         };
     }
 }